Adanson, M. (1763), Familles des Plantes 2: 116, 590 [tax. nov.]

• Type: (not designated).

Cassini, A.H.G. de in Cuvier, F. (ed.) (1826), Dictionnaire des Sciences Naturelles Edn. 2, 40: 188 [secondary reference]

• Type: Picnomon acarna (L.) Cass.

Eichler, Hj. (1965), Supplement to J.M.Black's Flora of South Australia (Second Edition, 1943-1957): 328 [secondary reference]

Anderberg, A.A., Baldwin, B.G., Bayer, R.G., Breitwieser, I., Jeffrey, C., Dillon, M.O., Eldenäs, P., Funk, V., Garcia-Jacas, N., Hind, D.J.N., Karis, P.O., Lack, H.W., Nesom, G., Nordenstam, B., Oberprieler, C., Panero, J.J., Puttock, C., Robinson, H., Stuessy, T.F., Susanna, A., Urtubey, E., Vogt, R., Ward, J. & Watson, L.E. in Kubitzki, K. (ed.) (2007), Compositae. The Families and Genera of Vascular Plants 8: 132-133 [secondary reference]

Mabberley, D.J. (1 May 2008), Mabberley's Plant-Book Edn. 3: 664 [secondary reference]

Council of Heads of Australasian Herbaria (2011), Australian Plant Census: - APC [secondary reference]

• APC Dist.: SA (naturalised), Vic (naturalised)

Bean, A.R. in Wilson, A.J.G. (ed.) (2015), Asteraceae Subfam. 2. Carduoideae Trib. 1. Cardueae. Flora of Australia 37: 57 [secondary reference]

• Etymology: "a classical name probably derived from the Greek pyknos (dense, compact) and nomos (an abode or a pasture), perhaps in reference to its bushy growth habit."

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